need help with IPC code

Hello folks-great site. I have not posted before. Can anybody look at my drain/vent scheme and give advice? I am replacing the ancient 4" cast drain and all the terribly connected fittings on 1915 house. I'm using a rubber no-hub to connect new 4" ABS to 4" cut stack in basement. Used 2 stack clamps in attic to make sure vent stack doesn't shift.

I think my scheme of combining the kitchen and bath sink before they hit the main stack is wrong. I originally had them going into opposite sides of the double tee (4x4x2x2) with the bath/shower going into a side inlet on the 3" toilet elbow-but a lot of guys like to have the toilet separate.....thanks for any insight on this, Dave

Vents are not right.
On the kitchen you have basically an "S" trap, drain goes down without a vent...
Where the drain enters the wall you should go up and tie the vent into the main stack in the overhead.
On a 1-1/2 drain you can go 3-1/2 feet before the vent. Vent must run vertical or at a 45 degree angle until it is 6 inches above the flood rim of the sink. you can then go horizontal.

I do not like the use of the AAV, those are ment to be a last resort, if the walls are open run the vent up and tie into the other vents, remember you have to tie in above the flood rim of whatever is being serviced.
Michael

Vent on the bathtub needs to go up higher as well. It needs to be six inches above the flood rim of the bathtub or toilet, which ever is higher at a minimum before tieing into the stack.

thanks for quick response Michael and Terry,I feel kind of dumb with the venting mistake. I missed the point of it needeing to be 6" above flood rim of what your draining. I can't bring the vent upward above kitchen, the wall above sink has been removed (not by me). back to drawing board. Glad asked early on.